// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2009 Benoit Jacob <jacob.benoit.1@gmail.com>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef EIGEN_MISC_IMAGE_H
#define EIGEN_MISC_IMAGE_H

namespace Eigen {

namespace internal {

    /** \class image_retval_base
  *
  */
    template <typename DecompositionType> struct traits<image_retval_base<DecompositionType>>
    {
        typedef typename DecompositionType::MatrixType MatrixType;
        typedef Matrix<typename MatrixType::Scalar,
                       MatrixType::RowsAtCompileTime,  // the image is a subspace of the destination space, whose
                                                       // dimension is the number of rows of the original matrix
                       Dynamic,                        // we don't know at compile time the dimension of the image (the rank)
                       MatrixType::Options,
                       MatrixType::MaxRowsAtCompileTime,  // the image matrix will consist of columns from the original matrix,
                       MatrixType::MaxColsAtCompileTime   // so it has the same number of rows and at most as many columns.
                       >
            ReturnType;
    };

    template <typename _DecompositionType> struct image_retval_base : public ReturnByValue<image_retval_base<_DecompositionType>>
    {
        typedef _DecompositionType DecompositionType;
        typedef typename DecompositionType::MatrixType MatrixType;
        typedef ReturnByValue<image_retval_base> Base;

        image_retval_base(const DecompositionType& dec, const MatrixType& originalMatrix)
            : m_dec(dec), m_rank(dec.rank()), m_cols(m_rank == 0 ? 1 : m_rank), m_originalMatrix(originalMatrix)
        {
        }

        inline Index rows() const { return m_dec.rows(); }
        inline Index cols() const { return m_cols; }
        inline Index rank() const { return m_rank; }
        inline const DecompositionType& dec() const { return m_dec; }
        inline const MatrixType& originalMatrix() const { return m_originalMatrix; }

        template <typename Dest> inline void evalTo(Dest& dst) const { static_cast<const image_retval<DecompositionType>*>(this)->evalTo(dst); }

    protected:
        const DecompositionType& m_dec;
        Index m_rank, m_cols;
        const MatrixType& m_originalMatrix;
    };

}  // end namespace internal

#define EIGEN_MAKE_IMAGE_HELPERS(DecompositionType)                     \
    typedef typename DecompositionType::MatrixType MatrixType;          \
    typedef typename MatrixType::Scalar Scalar;                         \
    typedef typename MatrixType::RealScalar RealScalar;                 \
    typedef Eigen::internal::image_retval_base<DecompositionType> Base; \
    using Base::dec;                                                    \
    using Base::originalMatrix;                                         \
    using Base::rank;                                                   \
    using Base::rows;                                                   \
    using Base::cols;                                                   \
    image_retval(const DecompositionType& dec, const MatrixType& originalMatrix) : Base(dec, originalMatrix) {}

}  // end namespace Eigen

#endif  // EIGEN_MISC_IMAGE_H
